Today we witness the dramatic growth and changes of the standards that the sporting gear must meet. As skating motion is gaining popularity, it has become necessary to enhance the ski boot sole resistance to twisting, because in this way the skier over a long period of time runs on the ski edge. In this case the sliding surface of the ski (and the boot sole surface as well) forms a substantial angle with the surface of the ski-truck (snow or snow-crust) bringing about strong twisting moments with respect to the boot sole when the skier pushes.
At present an "Adidas" ski binding is widely used, that consists of a plate with side-frames set at an angle to the longitudinal axis of the ski. The plate size and the value of the side-frames slope are determined by the size and shape of the boot sole toe complying with the "Racing Norm 38". The binding is designed for use with a ski boot that has a flange on the upper surface of the boot sole toe. The binding lock is designed in the following way. The plate carries a pin to which a lever is fixed that has still another pin at its free end. To this latter pin a second lever is fixed, the free end thereof holding down the flange of the boot sole toe. To lock the boot a skier must rest the end of the second lever against the boot flange and press the first lever which in this case keeps turning until the line connecting the two pins becomes lower than the line connecting the first pin with the rest point. To this position the boot gets locked. A high reliability of the design is one of the advantages of the latest modifications of the binding. Disadvantages of said binding include its considerable weight, relatively low adaptability to manufacture, relative complexity of the lock design, the necessity of using hands (ski poles) to lock or unlock the boot and considerable torques in the horizontal plane of the boot sole, the latter disadvantage being especially serious when a skating motion is used. Strong sole twisting is caused not only by the binding design but also by a narrow sole toe of a standard "Racing Norm 33" type boot which has a narrower toe as compared to the "Racing Norm 50" boot.
A ski binding of the "Rotafella" type widely used. This binding also consists of a plate with side-frames set at an angle to the longitudinal axis of the ski. As distinct from the "Adidas" binding, it has got three pins directly on the plate, which mate with the corresponding holes in the boot sole toe. The boot is locked with a shackle, free ends of which are set in sleeves of side-frames. In the foremost part of the binding there is an axle carrying a notched plate. The boot is placed in such a way that the holes in the boot sole toe mate with the pins. Then the skier presses the shackle into engagement with one of the notches in the plate. The binding may have different types of locks. For example, locks with eccentrics are widely used of late. Secure boot locking and a smaller torque occurring in the plane perpendicular to the ski longitudinal axis as compared to the "Adidas" binding mentioned above may be cited as advantage of said binding. Disadvantages include its considerable weight, relatively low adaptability of the binding and the lock to manufacture and, in particular, the necessity to use hands (poles) when locking and unlocking the boot.
There is a prior art ski binding which consists of rest pins, of two parts each, and a lock that restrains the boot vertical movement (cf. FRG Patent Application as published for opposition No. 3240750). One part of the pin is directly fixed in the ski (boot) and body, the other part fits in the corresponding boot sole (ski) hole. If the bottom part of the pin is fixed in the ski body, then, in order to lock the boot it is necessary to place it so that upper parts of the pins fit in the corresponding holes in the boot sole toe. To restrain the boot vertical movement various locks are employed. Advantages of said binding include relatively high adaptability to manufacture and simple design, its quick mounting and dismantling, use of different types of locks. Disadvantages include relatively poor functional qualities of the binding when locking and unlocking the boot because this can be done only manually.
A prior art binding (cf. FRG Patent No. G 8425984.1) comprises ski-mounted rest pins for mating with corresponding holes in the boot sole toe and a lock featured as a bracket-shaped blade spring for straddling from above the boot sole toe and having one end attached to the ski. High adaptability to manufacture, low production cost, small overall dimensions, light weight, automatic (no need to use hands) locking of the boot to the ski may be cited among its advantages. But this binding may be used only with ski boots that have a projecting sole toe or a welt. Accordingly, if a horizontal component force perpendicular to the ski longitudinal axis occur when the skier pushes, then a substantial torque is developed, as the skier's push zone does not coincide with the boot lock zone. Said disadvantage is characteristic of all types of binding designed for use with ski boots with a projecting toe and is most clearly manifested when skating motion is used.
Another serious disadvantage of said binding is that the lock in this design is adopted to a welt of a fixed thickness. The lock has proved to perform satisfactorily provided that the welt thickness does not deviate from the design value for more than 2 mm either way. This lock does not allow the use of the same binding with ski boots having substantially different welt thickness which is today characteristic of all widely used locks in bindings of various designs. Besides, said locks are intended for use with boots having a welt or a forwardly extended portion of the sole toe.